The present invention relates to a head gimbal assembly for a data recording disk file and more particularly to a head gimbal assembly in which the electrical conductors make a minimal contribution to the stiffness of the flexure.
Magnetic recording disk files that utilize a transducer mounted on a slider for reading and/or writing data on at least one rotatable disk are well-known in the art. In such systems, the slider is typically attached to an actuator arm by a suspension system.
The use of solder balls for attaching the slider to a slider support means is known in the art. For example, Ainslie et al., in U.S. Pat. No. 4,761,699, disclose the use of reflowed solder balls for making both the mechanical attachment of the slider to the suspension and the electrical connection of the transducer to the disk file read/write electronics.
The use of laminated materials for constructing slider suspension systems is also known in the art. For example, Erpelding et al., in U.S. Pat. No. 4,996,623, disclose a suspension system comprised of a sheet of polyimide material sandwiched between two metal layers. This patent also discloses that a plurality of conductors can be formed in the copper layer of the suspension for providing electrical connections to the slider. Additionally, the use of discrete layers for constructing the suspension is also known. For example, G. Oberg, in U.S. Pat. No. 4,819,094, discloses a suspension system in which flexible copper conductors are sandwiched between a pair of polyimide films.
Many suspension systems (also called head gimbal assemblies) include a flexure that is positioned in some manner between the slider and the suspension. For example, R. Watrous, in U.S. Pat. No. 4,167,765, discloses a flexure that is added onto a stiffened member. Blaeser et. al, in U.S. Pat. No. 5,198,945, disclose another design that utilizes the material of the suspension as the flexure.
A problem with both of these approaches is that it is difficult to make electrical connections between the magnetic transducer and signal conductors on the suspension without adversely affecting the pitch and roll stiffness of the head gimbal assembly.
An approach to reducing the influence of the electrical lead wires on the spring characteristics of the suspension is illustrated by M. Takahashi, in Japanese Kokai No. 53-30310. This document discloses a magnetic head assembly in which the electrical lead wires are imbedded in a flexible print plate which functions as a spring. Toshima et al., in Japanese Kokai No. 60-246015, disclose a similar system.
Briefly, the preferred embodiment of the present invention is a suspension system for supporting a magnetic read/write slider comprising a load beam for mechanically supporting a slider, a slider support member for providing a region on which the slider is mechanically attached, and a flexure for connecting the load beam to the slider support member. The flexure comprises a first flexure arm which forms a first outside edge of the flexure, and a second flexure arm which forms a second outside edge of the flexure. The first flexure arm is positioned closer to the disk hub than the second flexure arm.
A plurality of electrical conductors for electrically connecting a magnetic data transducer formed on the slider to the disk file electronic system, extend along the edge of the load beam on the side of the load beam that contains the second flexure arm. The electrical conductors are positioned adjacent to the second flexure arm, but are outside of the second flexure arm so as not to contribute to the stiffness of the second flexure arm.
In the preferred embodiment, the electrical conductors are comprised of a laminated material which includes a conductor layer, a dielectric layer and a support layer. The conductor layer is comprised of a high strength electrically conductive material such as a high strength copper alloy. The dielectric layer is comprised of an electrically insulating material such as a polyimide, Teflon or epoxy. The support layer is comprised of a nonmagnetic, high strength material such as stainless steel, titanium or beryllium copper.
In the region adjacent to the second flexure arm, the support layer is completely removed from underneath the conductors. In the region along the edge of the load beam, the support layer is removed from underneath the conductors which function as read lines. The use of high strength materials in the conductive layer allows the support layer to be removed in the regions described above, without making the conductors excessively fragile.
An alternative embodiment of the present invention comprises a suspension system having a flexure for connecting the load beam to the slider support member. The flexure includes a first flexible finger region which extends along a first outside edge of the flexure and a second flexible finger region which extends along a second outside edge of the flexure. A first plurality of slots extend completely through the first flexible finger region, and a second plurality of slots extend completely through the second flexible finger region.
A first plurality of electrical conductors extend along the first flexible finger region, and are positioned over the first plurality of slots. A second plurality of electrical conductors extend along the second flexible finger region and are positioned over the second plurality of slots. The slots provide region into which the electrical conductors can move when the flexure undergoes deflections, thereby reducing the contribution to the flexure stiffness made by the conductors.
The flexure is comprised of a laminated material which includes a conductor layer, a dielectric layer and a support layer. The conductor layer is comprised of a high strength electrically conductive material, such as a high strength copper alloy, thereby allowing the electrical conductors to be formed directly in this layer. The dielectric layer is comprised of an electrically insulating material such as a polyimide, Teflon or epoxy. The support layer is comprised of a nonmagnetic, high strength material such as stainless steel, titanium or beryllium copper.